checkbox-partial from coolicons in Line with regular corners. indeterminate, mixed, some, selection, box. Other styles and corners: @coolicons/<style>/<radius>/checkbox-partial with line, duocolor, duotone, fill or bulk and sharp or round. Leave out regular, like @coolicons/fill/checkbox-partial, and use @coolicons/checkbox-partial for line with regular corners.
pnpm dlx shadcn@latest add "https://coolicons.cool/r/checkbox-partial.json"